This continuing project is aimed at a greater understanding of the role that various portions of the brain, especially the mesencephalon and diencephalon, play in the conscious awareness of pain. The research is concerned primarily with an investigation of the neurons and fiber tracts involved in the production of pain that are not basically related to the classical neospinothalamic tract. These are, and have been, studied by (1) behavioral-shaping electrical stimulation of intracranial subthalamic, pulvinar (intralaminar system to be covered), tooth pulp (trigeminal) and radial nerve, (2) neuropharmacological drugs, (3) lesions of the most pertinent brain areas to determine if there is a block of escape (nociceptive) versus non-nociceptive behavior, as well as to evaluate changes in these behaviors that may occur long after an "effective" lesion, and (4) tracing of axonal fibers relevant to nociception.